Project 1

WIRING HARNESS DESIGN PROJECT 1

AIM:

Design and develop the Wiring harness on Given V6 Engine and Prepare flatten view drawing in CATIA V5. Application of all Packaging rules, Industry best practices studied in this course shall be demonstrated in design.

INTRODUCTION:

A wire harness, also commonly referred to as a wiring harness, is an exterior sheath used to cover some types of electronic wires. Generally, wiring harnesses are made of thermoplastic or thermoset materials that can help protect the cables from the environment.

ENGINE HARNESS:

An engine wiring harness is constricted wires, cables, terminals, and connectors controlling a vehicle’s electrical system. It relays electrical power and control information to components such as batteries, alternators, fuel injectors, fuses, audio systems, blower motors, fuel injectors, and computers. Wire harness companies customize it for every location, application, and design it interconnects. Also known as a cable harness, it is more than just a collection of multiple wires put together.

It manages the key functions around the engine including engine controller, oil controller gate, transmission plug housing, air pipe sensors, pressure sensors, and water temperature sensors.

An engine wiring harness is how each part of your vehicle gets electricity. It is crucial to help the vehicle run and it’s usually made of a heat-resistant rubber to handle the high and low temperatures that vehicles often experience. The vehicle needs more than the engine, and it requires a lot of electricity for certain things to function, like the radio or lights. Beyond that, battery, starter, and even alternator run on power, which is provided by the engine. Without an engine wiring harness, we couldn’t start your vehicle.

How Does the Engine Wiring Harness Work?

There are many cables in the engine wiring harness that work to connect electricity to your vehicle parts. This vehicle part has many sensors, and they work to ensure that everything in your vehicle is in working order. Some of these major systems in your car are fuel and transmission. When you get a check engine light, you have the engine wiring harness to thank.

It works by using these cables and a fuse box. They wire the electricity produced by the engine to the various parts and sensors. It is created using high-temperature plastic or rubber because the engine heats up a lot. That could cause the engine wiring harness to melt over time. And while this is a rare occurrence, it does happen.

Think of this part of the vehicle like the brain. Without it, it wouldn’t be possible to get the information your vehicle needs. It’s always working overtime to relay the data your vehicle needs to function correctly. Whenever a sensor goes off, it’s because the engine wiring harness alerted the sensor of the problem.

The exciting thing is that as vehicles get more advanced, the engine wiring harness grows. Some say that new cars have over 100 pounds of wires, so imagine how many things could go wrong with that. In the past, there may not have been many issues. However, as things advance, there are more to go wrong.

Engine Wiring Harness protection

Protecting the wires is crucial to the safety of the vehicle. Wires exposed to high temperatures, erosive chemicals and projectiles will be damaged leading to fires, brake failures and critical malfunctions. To prevent these issues, wires need to be bundled and covered.

install wiring insulation or heat shield sleeve material that can withstand direct contact with high-temperature surfaces and is flameproof. It needs to be a material built specifically for under hood automotive applications and withstand constant temperatures up to 125°C, or 257°F.

There are many options for protecting the wires in a vehicle’s harness. Zip ties securely bundle wire together but offer little protection or insulation. Plastic conduits offer protection from rough surfaces, although they can add weight and are not as flexible as other options. Heat-shrink tubing provides protection from heat, moisture and chemicals. However, the application is time-consuming.

Tape is another option for bundling and protecting wires. Tapes are more flexible and cost-effective than other bundling options because they can be used for protective wrapping, bundling and sealing. With a wide variety of backings and adhesives, tape can offer sound dampening, thermal and electrical insulation and abrasion protection of the same quality of the other methods. Additionally, tapes are more flexible, lighter and easier to apply than tubing or plastic conduit.

Wiring Harness Terms:

Wiring harness is the assembly of different systems, sub-systems in the vehicle. It won’t have any function; it depends on its system and sub-systems. It used to pass the signals between components.

Wires and Cables: The wiring harness is composed of numerous wires and cables of different gauges and colors. These wires are made of copper or aluminum, which are excellent conductors of electricity. The gauges and colors of the wires are standardized and follow specific industry conventions.

Connectors: Connectors are used to join different sections of the wiring harness together or to connect it to electrical components. They provide secure and reliable connections, enabling easy installation, maintenance, and repairs. Connectors can be of various types, such as plugs, sockets, terminals, or splices, and they often have unique shapes or keying to prevent incorrect connections.

Branches and Terminations: Wiring harnesses are designed to accommodate the complex electrical layout of a vehicle. They have branches and terminations that split off from the main harness to reach various components, such as the engine, lights, dashboard, entertainment system, or sensors. These branches ensure that the wiring reaches the required destination without excessive length or unnecessary complexity.

Protection and Insulation: Automotive wiring harnesses are typically protected by non-conductive materials, such as plastic or rubber sleeves, to prevent wires from chafing, short-circuiting, or getting damaged due to heat, moisture, or vibrations. Some areas of the harness may have additional protection, such as conduit or loom, to enhance durability and safeguard against environmental conditions.

Labeling and Identification: To simplify installation, troubleshooting, and maintenance, wiring harnesses often feature labeling or color-coding. Wires are marked with specific identification codes or labels that correspond to the vehicle's electrical diagrams or manuals. This makes it easier to identify individual wires and their intended connections.

Clips and clamps: Wide variety of clips and clamps are available to mount the wiring harness.

Fuse and relay box: are plastic moulded parts used to package Fuses and relays in systematic manner. It also protects them for any damage (Physical and Environmental).

Retention device: are plastic moulded parts to mount connectors and other harness components. (Connector mounts, secondary locks, connector back shell etc). Primary locking is provided by the terminal itself; secondary locks are not mandatory but there are used to ensure that there is no damage. Back shells are the packaging devices which are used at the end of the connectors. It guides the wire to the connector in a constrain packaging area or to provide the better appearance at the end of the connector.

Guiding channels: are plastic moulded or metal parts designed to guide harness bundle in given geometric area to secure and protect the harness.

Electronic components: Diodes, terminating resistors, Flasher, Timer circuits are sometimes part of harness supply.

Wiring Harness Routing:

Wiring harness routing refers to the process of arranging and securing electrical wiring harnesses within a vehicle or any other machinery. A wiring harness is a collection of wires, connectors, and other components that are bundled together to provide a centralized electrical connection and ensure proper functioning of various electrical systems.

During the manufacturing or assembly process, wiring harnesses are routed and positioned within the vehicle or machinery to optimize their functionality, ensure safety, and minimize the risk of damage or interference. This involves determining the most suitable path for the harnesses to follow, taking into account factors such as electrical requirements, space constraints, heat management, and protection against vibration or abrasion.

Wiring harness routing typically involves the following steps:

• Design and planning: Engineers or designers analyze the electrical requirements of the vehicle or machinery and create a wiring diagram that outlines the connections and components of the wiring harness. They also consider the physical layout of the vehicle or machinery to determine the most efficient routing paths.
• Path selection: Based on the design and available space, engineers select the optimal path for routing the wiring harness. They consider factors such as the proximity to electrical components, avoidance of heat sources or moving parts, and accessibility for maintenance or repairs.
• Mounting and securing: Once the routing path is determined, the wiring harness is mounted and secured using various methods such as clips, brackets, or adhesive tapes. This ensures that the harness remains in place and is protected from damage due to vibration or contact with other components.
• Testing and validation: After the wiring harness is routed and secured, it undergoes testing to verify proper electrical connections and functionality. This may involve continuity tests, insulation checks, and other electrical tests to ensure that the harness is correctly installed and operating as intended.

Design Criteria for Wiring harness:

• Wiring harness should be routed in following way that :
• it is easy to assemble on vehicle.
• It is easy to access in case of service or failure analysis.
• It should be secured properly so that it should not get damaged by surrounding component intraction.
• It should be kept away from heat zones like engine exhaust,mufflers,turbo chargers.
• It should be kept away from areas of direct water splashes.
• It should be kept away from sharp environment like sheetmetal bracket edges, corners, panel edges etc.
• It has to ensure human or machine intraction will not cause any dameges to harness.
• It should be kept away from driver or passanger reach zone.
• It should be kept away from High pressure fluid lines.
• Dynamic conditions of the vehicle should not damage the wiring harness.
• Keep harness away from tyre envlope.
• The harness should not be visible or exposed inside the vehicle.

Packaging Rules:

• Wiring harness routing shall provide ease in manufacturing, accessibility, easy removal, and easy maintenance of attached equipment and wiring harnesses.
• Routing through small structural holes and openings shall be avoided, minimizing chaffing and handling of the wiring harness during installation.
• Avoid the harness routing and clipping in the Blind zone of the Operator during harness assembly or in service.
• Routing shall offer protection against possible damage through common misuses such as being handheld and temporary support for test equipment.
• Provide additional slack to the harness according to the surroundings and harness bending requirements.
• Ensure the routing meets the clearance requirements with different surrounding parts.
• Routing shall provide enough slack for each branch to provide additional stress on wire and terminal crimping joint but also ensure extra slage creates wiring harness fouling.
• Avoid routing over the bolts, near the bolted joints. It may damage the harness or puncture the harness. Keep harnesses away from panel mounting screws.
• Avoid harness routing near sharp edges, if not possible provide protection to the harness.
• The maximum distance between two clips on a straight branch is 200mm.
• Provide Clips and clamps if the harness is going to bend at multiple locations.
• The use of too many sheet-metal brackets should be avoided.
• The branch length should be more than 50 mm.
• The minimium distance between the clip and the branching point is to be 25 mm.
• The minimium between two branch breakouts should be 50 mm.
• Use of rubber grommets is recommended if the harness is passing through sheet metal panels.
• Always keep the harness connector at higher than the harness routing and branching points, to make sure water does not enter due to gravity.

Assumptions :

• Provide clips/clamps as per requirement.
• Make sure that there is no falling case while designing the wire harness. Additional clips/clamps may be used to avoid falling cases.
• Give additional slack if needed. 5-10% slack is sufficient.
• Avoid routing over the bolt and bolted joints to avoid harness puncture.
• Avoid routing on sharp edges or else provide protection over the harness.
• Follow the clearance distance and keep away the harness from heat generation components.
• Protection should be provided as needed according to the surrounding temperature.
• Avoid direct support for harnesses on fuel lines routed in the engine.
• Use plastic guiding channels if needed.
• The branch length should be greater than 50mm.
• The minimum distance between two branch points should be at least 50mm.
• The minimum distance between the clip and the branch point should be at least 25mm.
• Avoid too many sheet metal brackets on the engine. Try to use available threaded bosses on the engine or demand for it.
• The wiring harness should be easy to assemble and easy to access.
• While using dummy connectors, ensure that whatever positions you are defining is practical. Bundle diameters and other placements can be defined properly for the wire harness routing.
• If the packaging area is too tight and there are many packaging constraints then we can think of creating a harness channel that can be used to route and protect the wire harness effectively.

Clearance Managment:

OBJECTIVE

• Define all the mechanical connectors electrically and save it in the Catalogue.
• Place all the connectors to the required positions on the given engine 3D CAD model
• Place P-Clamps and Fir Tree clips at the required position by following the packaging rules.
• Create the Wiring Harness Routing with all the electrically defined connectors and mounting equipments.
• Create branching points at required locations to create sub branches and connect to various connectors in the geometrical bundle.
• Apply Protection coverings as required.
• Create Wiring harness flattening for the final geometrical bundle.
• Using the drafting workbench, create a drawing sheet with the flattened wiring harness.

DESIGN METHODOLOGY:

Step 1- download the engine CAD data and required connectors CAD data from the given source.

Step 2- Download the required Connectors from the source and convert the mechanical connectors electrically by using the electrical part design work bench by following below steps.

• First download the connectors and mounting clip from the given link source.
• Get into the mechanical part workbench to create required geometrical parameters. Create connector connection point and bundle connection point on the required sides of the CAD part.
• Create axis system on the connector connection point such a way that the Y coordinate facing normal to the connector face, X coordinate facing towards the locking mechanism and Z coordinate facing to the top.
• Create cavity connection point for connectors having the cavity for mounting clips
• Using the geometrical parameters created,
• Define part as electrical connector.
• Define bundle connection point.
• Define connector connection point.
• Define cavity connection point

4 pole connector:

2 pole connector:

2-pole connector (C-282080-1):

2-pole connector (C-173090-2):

Inter Connection Connector (C-776438-4):

Adding Connectors to the Catalogue:

STEP 3- Download and Define the plastic channel electrically

Procedure for electrically defining the Channel.

• Create bundle entry point and exit point.
• Create a line curve between the main entry and exit points for creating the multi-branchable using external curve inside the channel
• Create 8 bundle entry points on the openings for connecting the injector connectors.
• Using the geometrical parameters, define the channel electrical using the define mounting equipment option.
• Create define bundle entry points using the “define bundle connection point option".

Then create a new product assembly with channel bottom and top part assembly

Create Channel symmetrical assembly and define the symmetry bottom channel electrically using define mounting equipment option and also create all the required geometrical parameters on it.

Channel Symmetrical Assembly

STEP 4-download and define P-clamp, L-clamp and cavity clip

STEP-5 CREATING CONTEXT ASSEMBLY

Context assembly is nothing but the product file which contains the engine 3D-CAD data and the engine harness geometrical bundle. Here the geometrical bundle product contains all the connectors and other mounting equipments, clips and clamps which are electrically defined for the assembly. Sheet metal L-clamp are added in the main context assembly. Then we need to switch into the Electrical Harness Assembly workbench and Geometrical Bundle Product file should be eelectrically defined using the Define Geometrical Bundle Option before adding any parts into it.

Step 6- Adding 4 pole connectors to all fuel injector sensors as well as for the camshaft sensors.

4 pole connectors connectors should be added in the geometrical bundle using copy and paste connector. Connectors can be added again by copy pasting the 1 st imported connector.

Place the Connectors on all the fuel injector sensors and cam-shaft sensors using the manipulation tools like move, smart move, snap tool and also using the compass.

Step 7 :- Adding all the other connectors for sensors like coolent heat sensor,neutral position sensor,speed sensor.

Step 8-: Add P-clamps for proper Routing of the harness Bundle.

Adding supporting components like p-clamps and firtree clip Can help the harness bundle provide proper routing and also help to prevent the Harness bundles fouling from unwanted mechanical components.

. P- clamp and the Fir Tree can be placed at required locations to ensure best possible routing for the Harness Bundles.

. The p-clamp can be mounted to the holes provided on the Engine Block in which the Screws to tighten the Engine Block.

Step 9:- Placement of channels at the required locations.use of plastic guiding channels are recommended to meet the clearance in critical areas if it is difficult to acheive by use of clamps.

• Some important packaging rules and best practices to be considered during wire harness routing and placing of the clips and clamps are as follows –
• Distance between two clamps on a straight branch should be minimum of 200mm.
• The minimum branch length should be 50mm.
• Minimum distance between clip and nearest branching point should be 25mm.
• The minimum distance between two straight connection points should be 200mm.
• The minimum distance between two breakout points should be 50mm.
• To limit the number of branches from a single branch point to 4.
• Avoid routing wiring harness near the exhaust manifold and its components and also from other unshielded heat sources. If re routing is not possible then maintain a minimum distance of 200mm.
• Try to avoid use of too many metal brackets on engine. Try to use the available threaded bosses on engine or demand for it.
• Enough clamps shall be provided to ensure positive clearance with surroundings and safety of wiring harness.
• P - Clamps, Fir tree clips and other clips can be added to the Geometric bundle as they are electrically defined and are part of the Wire harness routing and should be provided with the Wire bundle package.
• Enough slack should be provided to the wiring harness which help not to get damaged during the Engine rocking or starting condition.
• The wire harness routing should be done in such a way that it is easy in manufacturing and serviceability.
• The wire routing should be done keeping in mind the cost effectiveness of the bundle package.
• To avoid the harness routing and clipping in blind zones of the operator during the assembly and the service.
• To provide proper slack at end connectors so that there will be no tension on the wire bundle.
• To avoid sharp edges on the sheet metal parts and if it is not possible then provide protection parts to prevent damage of the wire bundle.
• To provide separate branch points for separate connectors to ensure Poka-Yoke.

Keeping all the above packaging rules we can start the routing of the wire and provide clipping and clamping wherever necessary during the routing process.

ENGINE with all the components for wiring harness routing.

STEP 10 - Wiring Harness Routing

• First, we need to create multi-branchable bundle using the external curve option and select the line which we created earlier.
• After creating the bundle segment, create 8 branch points inside the channel for creating sub branches for the injector sensor connectors
• Add branch points at minimum of 25mm distance from clips to create new sub branches connecting various connectors.

After completing the routing, we need to check that if any of the bundles is interacting with the Engine part.

There must be proper clearance between the wire bundle and the engine part.

Additional slack or Fir tree can be placed to ensure proper routing.

STEP 11 - ELECTRICAL CONTINUITY CHECK

• We need to ensure that the entire bundle is fully connected.
• Go to edit and then click on search command.
• Go to advanced
• Select workbench as electrical, type as bundle segment and attribute as Fully connected
• The select result should be as TRUE or FALSE and the click search to see the connectivity analysis result

Results

Selecting the "TRUE" option will show all the connected bundle segments while the selecting "FALSE" will show all the non-connected bundle segments.

For now, we will select "TRUE" and search for results. All the bundle segments are highlighted and found showing that all the bundle segments are electrically connected.

STEP12- After finally completing the wire harness routing by following the packaging rules we need to provide protection parts wherever necessary.

Slit- COT tubes, cotton tapes are added on the wiring harness bundle as shown below. The top part of the plastic guiding channel will also be added at this stage.

Following means can be used to protect the wiring harness in high temperature zones

Use of Corrugated tubes

They are of two types Slit and Non-slit Cot tubes

Corrugated flexible tubes also known as COT tubes / convoluted conduits have a wide range of applications in automotive industries.

Corrugated tubes are made from plastic and they are flexible.

Plastic materials used and its temperature resistance are as follows,

• Polypropylene (PP) for (-) 20 to 100 degree Celsius
• Heat Resistant (HR) for (-) 20 to 135 degree Celsius
• Flame Retardant (FR) for (-) 20 to 135 degree Celsius (flame retardant)
• Polyamide/nylon (PA) for (-) 20 to 180 degree Celsius

Use of breaded tubes (Nylon woven loom) and Silica sleeves –

In case of corrugated tube is not suitable for the very high temperature zones (specially in exhaust area), use of breathed tubes and silica sleeves can be done.

Beaded Tube- is an expandable sleeving braided from 8 mil(0.2mm) flame resistant polyphenylene sulfide (PPS) monofilament fiber, extremely lightweight, resistant to high temperature (up to 285 degree Celsius) and virtually impervious to solvents.

Silica Sleeve – it is braided into a strong and flexible sleeve from silica yarns. The thick 560mil (1.5mm) walls of this sleeving provide enhanced thermal protection up to 1800-degree Fahrenheit (982 degree Celsius).

Applying protection part to the required Harness Bundles

Selection of corrugated tubes are mainly driven by the wiring harness bundle diameter and temperature resistance requirements.

Black color tubes are widely used in automotive and off-road applications but other colors are also used to highlight the critical harnesses for example Emission system harnesses.

Final product

Step 13: WIRING HARNESS FLATTENING

Wiring harness bundle packaging process is done.now we need to convert the geometrical bundle into a flattened wiring harness in the Electrical Harness Flattening Workbench.

• To create the Flattened Harness, we need to create a new product file and switch into the electrical harness flattening workbench.
• Now we need to define the Harness Flattening Parameters and then Extract the geometric bundle from the wiring harness context product file.
• Then select all the branches and flatten the entire Geometric bundle.

STEP 14 – FLATTENED HARNESS VIEW IN THE DRAWING SHEET

Create a Drawing File for the flattened harness product.

• First, we need to make sure that in the flatten parameter settings bundles and protective coverings have different graphical representation which are,

Bundle Segments – Single line representation

Protective coverings – Double line representation.

• Create a new drawing file in the drafting workbench

Conclusion

In this project i have successfully routed the wiring harness for the V16 Engine assembly and the flatten-view drawing was prepared in CATIA V5. Various packaging rules and constraints were considered while routing the harness. After finalizing the wire routing, we can request the corresponding Engine design team to provide additional holes for the mounting of inter connection connector mounting bracket.